83b7933f8a
that switches from line-oriented to byte-oriented partway through, such as HTTP.
117 lines
3.1 KiB
C
117 lines
3.1 KiB
C
/*
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* Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/**
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* @file
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*
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* Line buffering
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*
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*/
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#include <stdint.h>
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#include <string.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <gpxe/linebuf.h>
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/**
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* Retrieve buffered-up line
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*
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* @v linebuf Line buffer
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* @ret line Buffered line, or NULL if no line ready to read
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*/
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char * buffered_line ( struct line_buffer *linebuf ) {
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return ( linebuf->ready ? linebuf->data : NULL );
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}
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/**
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* Discard line buffer contents
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*
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* @v linebuf Line buffer
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*/
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void empty_line_buffer ( struct line_buffer *linebuf ) {
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free ( linebuf->data );
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linebuf->data = NULL;
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linebuf->len = 0;
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linebuf->ready = 0;
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}
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/**
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* Buffer up received data by lines
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*
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* @v linebuf Line buffer
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* @v data New data to add
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* @v len Length of new data to add
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* @ret rc Return status code
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*
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* If line_buffer() returns >0, then an end of line has been reached
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* and the buffered-up line can be obtained from buffered_line().
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* Carriage returns and newlines will have been stripped, and the line
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* will be NUL-terminated. This buffered line is valid only until the
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* next call to line_buffer() (or to empty_line_buffer()).
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*
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* @c data and @c len will be updated to reflect the data consumed by
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* line_buffer().
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*
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* Note that line buffers use dynamically allocated storage; you
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* should call empty_line_buffer() before freeing a @c struct @c
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* line_buffer.
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*/
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int line_buffer ( struct line_buffer *linebuf,
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const char **data, size_t *len ) {
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const char *eol;
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size_t consume;
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size_t new_len;
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char *new_data;
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/* Free any completed line from previous iteration */
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if ( linebuf->ready )
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empty_line_buffer ( linebuf );
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/* Search for line terminator */
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if ( ( eol = memchr ( *data, '\n', *len ) ) ) {
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consume = ( eol - *data + 1 );
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} else {
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consume = *len;
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}
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/* Reallocate data buffer and copy in new data */
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new_len = ( linebuf->len + consume );
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new_data = realloc ( linebuf->data, ( new_len + 1 ) );
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if ( ! new_data )
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return -ENOMEM;
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memcpy ( ( new_data + linebuf->len ), *data, consume );
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new_data[new_len] = '\0';
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linebuf->data = new_data;
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linebuf->len = new_len;
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/* Update data and len */
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*data += consume;
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*len -= consume;
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/* If we have reached end of line, trim the line and mark as ready */
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if ( eol ) {
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linebuf->data[--linebuf->len] = '\0'; /* trim NL */
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if ( linebuf->data[linebuf->len - 1] == '\r' )
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linebuf->data[--linebuf->len] = '\0'; /* trim CR */
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linebuf->ready = 1;
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}
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return 0;
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}
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